1. Field of the Invention
The present invention relates to a push button. More particularly, it relates to a push button comprising a button body and a panel body wherein the inside is invisible through a clearance between the button body and the panel body when the button body is pushed into the panel body. Moreover, it relates to a push button which hardly damages interiors such as circuit substrates and switches.
2. Description of the Related Art
The operations of various apparatuses are controlled with switches which are disposed on and assembled with a circuit substrate. In such apparatuses, the circuit substrate is held in a case, and accordingly switches disposed on the circuit substrate are also held in the case. The switches are operated in turn with operating means, such as push buttons, disposed in the case.
A push button for such an application is disclosed in Japanese Unexamined Patent Publication (KOKAI) No. 2000-306,460, for instance. The patent publication discloses a display apparatus in which an operating portion of a push button for switching is fitted into an opening in a panel structure (or an exterior panel) of a display unit and is supported by an elastic member. The display apparatus is characterized in that the push button has a tapered structure on a rear side of the operating portion; the panel structure has an inclined portion disposed at an opening periphery on a rear side of the opening; and a restoring force of the elastic member pushes the tapered structure onto the inclined portion.
In the push button disclosed in the patent publication, the inclined surface disposed at the opening periphery in the panel structure is brought into close contact with the tapered surface in the tapered structure disposed on a rear side of the operating portion of the push button. Thus, the push button is positioned with respect to the panel structure with high accuracy.
In such a conventional push button, the pushing-in of the operating portion is regulated by the elastic member alone. Accordingly, there is a fear that the push button might be damaged when the operating portion is pushed in too hard. Moreover, when the operating portion is pushed in too hard, excessive forces are applied to a switch, which is operated by the push button, and a circuit substrate, with which the switch is assembled. Consequently, there is a problem that damages might occur in the switch and circuit substrate.
Moreover, in such a conventional push button, a clearance exists between the outer peripheral surface of the operating portion of the push button and the inner peripheral surface of the panel structure. When the operating portion of the push button is pushed into the panel structure, interiors such as the circuit substrate which is hidden inside is visible through the clearance between the operating portion and the opening of the panel structure. Thus, there arises another problem that the appearance of the display apparatus might degrade.